Resistance: 12mΩDo not charge by Nitecore Intellicharger or some so call intelligent charger that could charge different battery models.Charge by 4.2V Li-ion 18650 Charger only!Note: It is not a good idea to mix new and old batteries! We do not advise buyer to mix different brand, different spec., fresh and half-used ( or dead ) battery in use. When mixing a new battery at full capacity and a used battery at a diminished capacity can cause harm to the batteries and your device.When the batteries in your electronic device finally give out, its a correct way to replace each and every battery with the same batch in it.